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    7 Common Causes for Your Water Heater Making Noise

    Noisy Water Heater

    It's not uncommon for your water heater to be making noises, and besides the fact that it's just down right annoying, it could be an indication that there's something wrong with your heater that needs to be corrected. Even if you perform regular maintenance on your heater, you could still experience a noisy water heater.

    Taking the time to diagnose the problem will not only quiet things down, but it could help you prevent further damage. This article covers the top 7 reasons you may be experiencing a noisy water heater.

    Our Guide to What Causes a Noisy Water Heater


    Man holding his ears

    Accumulation of Sediment & Mineral Deposits

    If your water heater has a significant amount of sediment and mineral deposits you might hear any of the following noises:

    Popping

    Over time sediment accumulates inside the heater's tank. This is why performing regular maintenance is so important. Flushing the debris is probably the single most important thing you can do to keep your water heater running efficiently, not to mention maximizing it's service life.

    Sediment is defined as any solid material that settles on the bottom of your water heater. Your water heater collects sediment in two ways: 

    • It comes in with the water supply in the form of sand or other debris.
    • Its minerals which are released when the water is heated.
    Mineral Deposit Build-up

    Mineral deposit build-up is especially a problem in areas with hard water. Water absorbs minerals as it travels through the ground. These minerals, primarily calcium and magnesium carbonate, are harmless from a health perspective.

    However, as water is heated, the minerals separate from the water and coat the inside of the tank, along with the components. This coating is called lime scale and the popping sound you hear may be the result of lime scale build-up.

    Sediment Build-up

    When a water heater is not flushed on a regular basis, sediment begins to collect at the bottom of the tank. As the water heater heats the water, steam bubbles can develop underneath the sediment and explode. The popping sound you hear may actually be the steam bubbles exploding!

    Although, flushing the water heater is the solution to this problem, it may not be the best answer. In some cases, the sediment build-up can reach a point where flushing the tank is no longer possible and may cause your tank to leak.

    When this is the situation, your best move is to purchase a new water heater. However, some homeowners choose to wait for their heater to fail. If this is the route you'd like to take, we highly recommend purchasing a water alarm to alert you to leaks. There's nothing worse than discovering multiple gallons of water on your floor!

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    Rumbling

    As the water temperature rises, the water within the tank expands and begins to escape from under the sediment. The rumbling sound you hear is the water making its way through the sediment.

    If you're able to hear a rumbling sound, there's a good chance  that the sediment build-up has reached a critical level. Although, not dangerous, it is an indication that your water heater is not operating efficiently.

    You should attempt to flush the sediment build-up from the tank. As we discussed above, this is a red flag that your tank may be prone to having future problems which may require you to replace it in the near future. We highly recommend purchasing a water alarm to alert you when your tank begins to leak.


    Crackling, Sizzling, Hissing, or Popping

    If your electric water heater is making a popping noise there's a good chance that the sediment build-up at the bottom of the tank has buried the lower heating element. This condition can also make sounds of crackling, sizzling, or hissing.

    When this happens, you should drain the tank and remove the heating element so you can clean any sediment and lime scale build-up from the element.  

    Soak the heating element in vinegar and then gently use a wire brush. In most cases, you can clean them, but occasionally your best move is to purchase a new one.

     
     
     
     

    Heating Element

    Rheem SP10869MM Screw-In 240-volt by 4500-watt Element, Premium Resistored Stainless Steel

    If you need to purchase a new heating element, make sure you find the right one for your water heater.

    If your water heater won't drain because the sediment build-up is clogging the drain valve, don't panic. We've written an article with a number of different methods to unclog your water heater. However, even if you drain your tank, you may need to purchase a new water heater in the near future.

    Many people choose to wait until their tank begins to leak before replacing it. If this is the path you choose, we highly recommend purchasing a water heater leak detector.

    These alarms help prevent a huge mess by alerting you when the sensors detect water leaking from the tank. They're inexpensive and easy to use, best of all they'll allow you to react quickly before you have 60-gallons of water on the floor!

     

    Water Alarm

    Glentronics, Inc. BWD-HWA 00895001498 Basement Watchdog High Water Alarm, Multi

    This inexpensive water alarm can save you hundreds of dollars in water damage.


    Restricted Water Flow

    Sizzling

    If you find your water heater is making noise when the hot water is turned on, it could be caused by restricted water flow. When this is the case you'll often hear a sizzling sound and it may indicate an issue with a valve.

    •  
       
      Check the T&P relief valve. This is a safety valve designed to allow water to escape if the tank ever builds up too much pressure. If the sizzling sound is coming from the T&P valve, we recommend shutting down the water heater by turning off the power and water. Then contact a professional plumber.
    •  
      Check the water inlet valve to ensure it's fully opened. This is the water valve on top of the heater which allows the incoming water to enter the water heater.
    •  
      Check all of the other water lines and valves, including the water outlet valve to make sure there are no kinks in the lines and that the valves are fully opened.

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    Water Pressure Fluctuations

    Ticking

    A ticking sound is typically caused by pressure fluctuations within the plumbing. Frequently, water heaters use water inlet and outlet nipples with heat traps which helps improve the unit's energy efficiency by not allowing the heat to escape through the connections.

    The nipples are located on top of the water heater where the incoming and outgoing water plumbing connects. If you find that this is the source of the ticking sound, you can simply remove and replace them with non-heat trap nipples

     
     
     
     

    Dielectric Nipples

    Camco 10623 Dielectric Nipples

    Changing your heat trap nipples to these dielectric nipples can eliminate the annoying ticking sound your water heater makes.


    Household Plumbing

    If your water heater is making noises it could be the result of your household plumbing. In fact, the problem may not be your water heater at all.

    As the hot water travels through your home's plumbing, the pipes expand and contract when the water temperature warms and cools. This can sometimes cause the pipes to rub against the wood framing or loose straps and result in a ticking sound. 

    To fix this problem you can follow the sound and try to pinpoint where it's the loudest. Then secure the pipe tightly or install spacers to keep the pipes from moving.

    Another possible fix is to lower the temperature of the water heater by a few degrees. This should reduce the pressure which, in turn will hopefully eliminate the noise.

    head phones lined up on a pipe

    Leaks & Condensation

    Running Water

    If your water heater is making noise like water is running, you probably have a leak or a broken pipe. Although, keep in mind that it is normal to hear water entering the tank when hot water is being drawn.

    If the running water noise continues once the tank is filled, you may want to call a professional plumber to investigate the situation for you. Or, you can try to run down the leak yourself by checking the following: 

    • Check the temperature of the hot water outlet pipe on the water heater. The hot pipe may feel warmer than the cold pipe, but if no hot water is being used, it shouldn't feel hot to the touch.
    •  
      Position your ear next to the hot water outlet pipe. If no hot water taps are open you shouldn't hear water moving through the pipe. If you hear water running, you have a leak.
    •  
      Check the T&P Valve. There's a long tube attached to the T&P Valve and sometimes the tube runs directly into a drain or through a wall. If this is how your heater is configured, it's difficult to see if the T&P Valve is open. Check the temperature of the pipe with your hand. If it is hot, your T&P Valve is most likely open. Carefully open and close the valve to see if that stops the flow of water. If not, you'll need to replace the valve.
    •  
      You may have a broken pipe somewhere in your home. Check the reading on your water meter and do not use any water for several hours. Then check the reading again. If the water meter indicates that you used water, you most likely have a broken pipe.

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    Sizzling

    If you have a gas hot water heater and you notice a sizzling sound when the burner is ON, there's a good chance that you have an issue with condensation.

    When condensation forms it can drip onto the burner components and, when the burner is hot, you'll hear a sizzling sound.

    Water Heater Leaks

    A sizzling sound could also be caused by a leak inside the water heater. When this is the problem, you'll typically hear the sizzling sound when the burner is OFF.

    Check your water heater for leaks, you may even find a puddle nearby. In many cases a sizzling sound is cause for contacting a professional plumber.

    Water Source

    Popping

    If your anode rod is made of aluminum and your water supply has a high pH level, a reaction called aluminum hydroxide may occur. This is actually a very common issue in areas that have chlorine/chloramines in the water supply, since chlorine has a pH level of 11.7.

    When this reaction occurs, a gel-like substance forms at the bottom of the tank and/or the anode rod. If this is your problem, you'll need to flush and delime your tank, and then replace the  sacrificial anode rod with one made with magnesium. 

     
     
     
     

    Magnesium Anode Rod

    About Fluid | Magnesium Flexible Anode Rod Kit for Water Heaters | Teflon Tape | Easy-to-Follow, Step-by-Step Instructions | 44 Inches Long. (Without Socket and Cap)

    This flexible magnesium anode rod requires less head space to install.


    Water Hammer

    Knock or Hammer Sound

    If your hot water heater is making a knocking noise, it could be an issue called water hammer.

    When the water flow is abruptly stopped, there's no place for the water to go within your household plumbing, so it flows in reverse back to its original source. In this case, your water heater. 

    The sound you'll hear is typically a knock or a hammer sound, and it happens when the water is abruptly shut off. Water hammer can be very destructive. Even though the problem did not originate from your water heater, it could create a serious damage to the appliance.

    There's enough force within the pipes to cause the water heater's tank shell to expand, or collapse a flue tube, or even deform the top of the heater's tank! Not to mention it could cause a pipe to burst within your home.

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    Installing a Water Hammer Arrestor can protect your plumbing and water heater. These devices absorb the shock wave  created when the flow of water abruptly ends.

     
     
     
     

    Water Hammer Arrestor

    Sioux Chief Mfg 660-TK Female Swivel Ballcock Nut by Male Ballcock Thread Mini Rester

    A water hammer arrestor is designed with an air chamber that will absorb the shock when the pressure within the plumbing reaches the device.


    Heating Element

    Humming

    If you notice your electric hot water heater making a humming noise the problem may be with the top heating element.

    There are two heating elements, an upper and a lower, and it's not uncommon for the upper heating element to vibrate and hum when cold water flows into the tank and circulates around the system.

    Although annoying, when your water heater is making a vibrating noise it's generally not harmful to either the heating element or the water heater. You can typically fix the problem yourself by using an element wrench to tighten the heating element

     
     
     

    Heating Element Wrench

    Camco 09953, TRV117743

    This heating element wrench will tighen an electric water heater's heating element.


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